This invention relates generally to truck mounted collector apparatus and more particularly to a multi-stage truck mounted vacuum collector apparatus having several particulate material collection chambers adapted to selectively discharge collected particulate materials from a common discharge point.
Portable, heavy-duty vacuum collector apparatus are commonly used in industrial and other applications to collect wet and/or dry particulate materials. In industrial applications such as at foundries and manufacturing plants, in particular, the apparatus may be used to collect waste materials and spillage such as slag, steel shot, sand, ash, carbon black and the like. As a matter of economy, a vacuum collector apparatus may be used to collect various materials varying widely in particulate size and weight and, in some cases, even water. For example, operations at foundries normally result in the accumulation of wet and dry sand, often admixed with metal chips from casting and metal shop spillage from cast cleaning. Efficient foundry operation requires removal of those materials. Manufacturing plants also use conveyors, grinders, pneumatic chisels, wire brushes, machine tools, and other power tools and machines producing dust and other particulate materials. Such use gives rise to serious health, safety, and machine maintenance problems which can only be eliminated through continuous removal of such materials.
Because of the diversity of the materials collected, such vacuum collector apparatus preferably comprises a self-contained multi-stage unit wherein each one of the several stages is utilized to remove particulate materials or spillage in a particular size and weight range. The three-stage apparatus in U.S. Pat. No. 3,780,502, issued to Dupre et al., has been found to be quite effective in such applications. In that apparatus, heavier particulate materials suspended in the intake airstream are removed from the airstream in a cyclone separator stage according to well known physical principles of heterogeneous material flow. Subsequently, the airstream, still carrying lighter particles, is drawn through a vertical downwardly extending linear accelerator nozzle to remove the heaviest of the remaining materials therefrom. Finally, the airstream is directed through a plurality of fabric, flat bag, filter elements which filter out and remove substantially all of the remaining particulate material in the airstream and, in particular, dust.
Often, the spillage materials to be collected by the apparatus are found at different locations in the plant and are not easily reached by a stationary vacuum apparatus. Mobile vacuum apparatus have been provided heretofore in the form of self-propelled mobile units. Such units have commonly included a first box in which heavier refuse is collected and a dust container for collecting dust and lighter weight waste materials. These materials are commonly emptied from the box and the dust containers through respective individual doors provided therein. Thus, with some units, if the materials are to be emptied at a single discharge point, the unit must be repositioned at the discharge point as first the box and then the dust container are unloaded.
Another prior art apparatus comprises a self-contained suction type cleaning unit having a rearward hopper for collecting heavier dirt particles and refuse and an adjacent forward dust bin in which dust and lighter particles are deposited. The hopper and the dust bin are separated during normal vacuum operation by a swinging door covering an opening in the wall between the hopper and the dust bin. The collected waste materials are emptied from the hopper and the dust bin by tilting a frame supporting the hopper and the dust bin to discharge the collected particulate matter through the rear tailgate. The swinging door covering the opening between the two chambers allows the materials collected in the dust bin to empty through the hopper. When the particulate waste material collected in the hopper contains some moisture, however, the apparatus may be clogged. That is, the heavier particulate matter may cake in the hopper and prevent the swinging door from opening during discharge. As a result, unless the operator cleans the hopper by removing the caked particulate matter to free the swinging door, the dust may be trapped in the dust bin and ultimately impair the operation and effectiveness of the vacuum collector apparatus.